Pressure loaded pump



Aug. 21, 1962 J. E. THRAP EIAI 3,050,010

PRESSURE LOADED PUMP Filed Feb. 23, 1960 2 Sheets-Sheet 1 Join f. 7721a; Hefiert FFrasse J4, kl/J 4 11 IDVEDTEIFE.

Aug. 21, 1962 J. E. THRAP EIAI.

PRESSURE LOADED PUMP 2 Sheets-Sheet 2 Filed Feb. 23, 1960 Her art 5 Frzsse United States Patent 3,050,610 PRESSURE LOADED PUMP John E. Thrap, Willoughby, and Herbert F. Prasse, Gates Mills, Ohio, assignors to Thompson Raine Wooldridge Inc., Cleveland, Ohio, a corporation of Ohio Filed Feb. 23, 1960, Ser. No. 10,446 4 Claims. (Cl. 103-126) This invention relates generally to pumps and more particularly relates to a pressure-loaded gear pump characterized by improved means of pressure loading end plates or pressure plates engaging the adjoining side face of the driving and driven gears.

It is an object of the present invention to provide a pump wherein an improved construction fabricated with simplified economically produced elements may be employed.

A particular object of the present invention is to provide a pump wherein a die cast cover plate may be utilized and wherein no movable bushings are required in the pump body but wherein the full advantages of pressure loading of a movable end plate or pressure plate may still be obtained.

Yet another object of the present invention is to provide a pressure loading arrangement wherein a webbed gasket cooperates with a confining means including a flexible wafer to form inlet and outlet zone sectors so that pump-generated pressure may be confined within a specified zone for balanced pressure loading.

Many other features, advantages and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description which follows and the accompanying sheet of drawings.

On the drawings:

FIGURE 1 is an elevational view of a pump incorporating the principles of the present invention;

'FIGURE 2 is a cross-sectional view taken generally on line IIII of FIGURE 1;

FIGURE 3 is an elevational view, fragmentary in part and illustrating additional details of construction of the pressure loading means utilized in accordance with the principles of the present invention; and

FIGURE 4 is an exploded view of the pressure loading means of FIGURE 3.

As shown on the drawings:

The pump of the present invention is indicated generally at and comprises a casing 11 having an inlet 12 and an outlet 13 with a pumping cavity or pumping chamber 14 formed therebetween. The casing 11 is closed by a closure plate 16 at one end and in accordance with the principles of the present invention, the other end of the casing 11 cooperates with a cover plate 17 which, by virtue of the novel structural provisions incorporated therein, may conveniently be fabricated as a die casting. The cover plate 17 is shown connected to the casing 11 by a plurality of fasteners 18.

Rotatable Within the pumping chamber 14 is the rotatable fluid displacement means of the present invention comprising a driver gear 20 and a driven gear in mesh therewith. Both the driver and driven gears may conveniently be fabricated in accordance with a twopiece construction. For example, the driver gear 2% may conveniently comprise a gear hub 21 having a plurality of circumferentially spaced teeth on the periphery thereof and press-fitted onto a shaft part 22 including a shaft extension 23 journaled in a bearing area 24 formed in the casing member 11 and a shaft extension 26 journaled in a non-floating cover bushing 27 carried in the cover member 17, the shaft extension 26 having a portion 28 extending outwardly of the cover member 17 for attach- 3,059,016 Patented Aug. 21, 1962 ment to a power source for rotatably driving the gears in the pump.

The pump It) does not require body thrust plates, rather, the pumping cavity 14 has a thrust face 29 formed adjacent a corresponding side face 30 of each respective gear such as the gear 21 The opposite side face 31 of each respective gear such as the gear 20 is engaged by a sealing face 32 formed on an end plate means indicated generally at 33 and formed in accordance with the principles of the present invention by a pair of pressure plates or end plates, each of which is of identical construction and each of which will be described in connection with the same reference numerals.

Referring more specifically to FIGURES 3 and 4, it will be noted that the cover member 17 is particularly characterized by the formation thereon of an axially extending boss 34 having formed therein shaft openings 36 and 37, respectively, each adapted to receive the corresponding shaft extension of a corresponding driver or driven gear such as the driver gear 20. Pressed in non-floating assembly within the boss 34 of the cover member 17, is the bushing 27.

The general contour of the boss 34 is such that a flat planar surface 33 is provided which is slightly larger than the adjoining pumping chamber 14 of the pump 10, but which is complementary in size and shape with respect thereto. Thus, the planar surface has spaced lobe portions separated by a reduced section indicated at 39.

The remaining elements of structure can be conveniently described in connection with an assembly operation of the pump. First of all, when the pump is assembled the closure plate 16 is affixed to the casing 11 whereupon the gears, including the driver gear 21!, are dropped in place in their respective pockets, for example, so that the shaft extension 23 is journaled within the bearing surface 24, and so that the side face 30 engages against the thrust face 29 of the casing 11.

Thereupon, a pair of pressure plates or end plates 33 are assembled over the opposite shaft extensions of the gears, for example, the shaft extension 26. Note that each end plate 33 comprises a flat plate-like member which is generally circular in configuration, the outer circular periphery of each end plate 33 being indicated at 4th and characterized by the formation of a flattened chordal portion 41, thereby to provide adjoining abutment surfaces so that the pair of end plate members 33 together form a generally figure (y-shaped end plate sealing means. Further, each end plate 33 has a shaft opening 42. As noted previously, the end plate members 33 provide a sealing face 32 for engaging against the adjoining side face 31 of the gears. It will be noted upon referring to FIGURE 2, that the outer periphery 40 of the end plates 33 slidingly engage against the adjoining wall 43 of the casing 11, which wall 43 prescribes the outside boundary of the pumping chamber 14. The diameter of the inner periphery 42 of each shaft opening in the end plate members 33 is sized to slidingly engage the outside peripheral surface of the nonfifloating bushing 27 carried by the cover member 17.

Once the pressure plates 33 are in place, a first wafer member indicated generally at 44 is assembled thereover. The wafer member 44 conveniently comprises 'a thin sheet form member made out of phenolic material, or out of any other material capable of limited flexure. The first Wafer member 44 has a pair of shaft openings 46 and 47, thereby to facilitate mounting of the wafer member 44- on the spaced bushings 27 carried by the cover member 17.

On the discharge side of the pump, the first wafer member 44 is characterized by the formation of an opening 48. The opening 48 appears to have two kidneyshaped sectors together with an enlarged medial section.

Such opening can be formed by punching out the area prescribed by the opening 48, thereby forming another separate wafer member indicated at 49. Thus, the wafer member 49 has first and second kidney-shaped lobes indicated at 50 and 51, respectively, together with a central cover member 17. Thus, the reduced center section 54 is adapted to lie in register with the correspondingly reduced center section 39 of the surface 38. The outer margins of the wafer member 44 overlie the casing 1'1 at the edges of the wall 43 forming the pumping chamber 14.

In the next assembly step, there is provided a stamped gasket which is shown generally at 56. The overall configuration of the gasket 56 is the same as the plane surface 38 of the cover member 17, however, in specific reference to the structural characteristics of the gasket 56, it will be noted there is provided an outer peripheral web 57 which conforms to the outer peripheral edge of the plane surface 38, as well as the outer peripheral edge of the first wafer member 44 and also an inner web 58 which is formed to provide two shaft openings 59 and 60, respectively, each of which receives a corresponding bushing 27 therethrough. A center rib 61 interconnects the loops'formed by the inner web in prescribing the openings 59 and 60, and a dividing rib 62 extends from the center rib 61 and between the inner web 58 and the outer web 57.

Formed at approximately a 45 angle to the shaft openings 59 and 60 are a pair of dividing ribs shown at 63 and 64, respectively. Thus, the gasket 56 prescribes an inlet zone sector identified at 66 and an outlet zone sector 67 having two components separated by the divid- There is also provided a second wafer member indicated generally at 68 formed with shaft openings 69 and 70, respectively, and like the gasket member 56 and the first wafer member 44, shaped and sized to be complementary to the plane area 38 on the cover member 17. It may be noted that the inlet zone sector 66 prescribed between the inner and outer webs 57 and 58 and the dividing ribs 63 and 64 of the gasket 56, is sized and shaped to receive the web member 49 therein. Thus, the web member 49 reinforces and supports the webs of the gasket.56 against collapse due to pressure displacement. It will be appreciated that the gasket 56 is sandwiched between the first and second wafer members 44 and 68. Thus, in operation fluid at pump-generated discharge pressure is supplied from the gear cavity 14 close to the mesh point of the gears on the discharge side of the pump through the openings 70 and 71, which are left adjacent the mesh point by the curvature of the end plate means 33, and through the opening 48 of the first wafer member 44 into the discharge zone sector 67.

By virtue of the area prescribed by the discharge zone sector 67, the force exerted against the end plate members 33 via the first Wafer member 44 will balance or slightly exceed the pressures in the gear cavity '14 on the pressure side of the pump.

Inlet pressure in the pump is referenced from the gear mesh area at the inlet side of the pump to the inlet zone sector 66 via the opening 53 formed in the first wafer member 44. Moreover, by virtue of the pressure yoke provided by the wafer member 49 being located in the zone 66, the sealing web action of the webs 57 and 58 of the gasket 56 are supported against collapse even though there is a large pressure differential between the zone 66 and the zone 67.

The selection of the areas of the two zones 66 and 67,

4 of course, permit an exact balanced condition to be obtained for all pump operating conditions.

The final step in the assembly of the pump, of course, is the assembly of the cover member 17 with the plane area 38 overlying the second wafer member 68. The non-floating bushings 27 pass through the various openings identified in each of the respective members and the fasteners 18 are used to place the cover member 17 in firm assembly with the casing 11. It will be noted that the cover member 17 is provided with a sealing member 76 adjacent the projecting portion of the shaft extension 26. The seal cartridge is clamped at its outer margin between the boss 34 of the cover 17 and the casing 11. The clamping pressure, of course, is regulated by the amount of take up on the fasteners v18. In other words, the cover member 17 engages the second wafer member 68 and is positioned outwardly thereof and applies an axial holding force holding the wafer members 68 and 44 and the gasket 56 inwardly against the pressure plates 33. The gasket 49 is thus squeezed between the wafer members with a force sufiicient to maintain the gasket in sealing engagement with the two wafer members even though minor shifting of the end plates may occur with fluid pressure loading. The gasket can expand axially but still remain in sealing contact with both wafer members. The wafer member 44 is sufficiently flexible so that it can be bent or deformed relative to the projecting shoulder of the casing 11 to maintain engagement with the end plates 33 if there is any shifting axially with pressure loading.

We have thus provided a pump construction which facilitates the utilization of economically produced parts, for example, parts made by die casting methods and wherein no movable bearings are required in the pump body but still retaining all of the advantages of balanced pressure loading of pressure end plates.

Although various minor modifications might be suggested by those versed in the art, we wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art.

We claim as our invention:

1. A pressure loaded gear pump comprising a casing having a pump chamber formed with an inlet and an outlet, meshing driver and driven gears in said chamber for moving fluid from said inlet to said outlet, a rigid end plate means closing one end of said pump chamber and having a front sealing face engaging the adjoining gear side faces, and having a rear face forming a motive surface, a first wafer member having one face engaging said rear face of said end plate means and having an opening formed therein of a double kidney configuration opposite the discharge side of the pump and further including a pair of openings opposite the inlet side of the pump, the margins of said first wafer member overlying said casing at the edges of said pump chamber, said wafer member being sufliciently flexible to bend about its margins for continued engagement with the rear face of said end plate means with axial movement of said end plate means, a shaped rubber gasket engaging the opposite face of said first wafer member and including an outer peripherally continuous web co-extensive in length to the adjoining peripheral portion of said first wafer member, a pair of inner peripherally continuous webs co-extensive in length to the adjoining bearing journals for the pump gears, cross webs interconnecting said inner webs and including a dividing rib connected to said outer web across the discharge side of the pump to rigidify the gasket, and a pair of cross webs interconnecting the inner and outer ribs on the inlet side of the pump, thereby to form within the gasket a pair of discharge zone sectors on the discharge side of the pump separated by said dividing rib and an inlet zone sector on the inlet side of the pump, an insert wafer corresponding in size and shape to said inlet zone sector and received therein to support said gasket against collapse, a second wafer member co-extensive in area with said gasket, and a cover member for said pump abutting against said second wafer member, said gasket sealingly squeezed between said wafer members and being expandible axially to maintain sealing relationship with the wafer members with axial shifting of the end plate means and first wafer member, whereby said first and second wafer members are clamped between said casing and said cover member and form together with said gasket a pressure control means to pressure-load said rigid end plate means with inlet pressure over an area corresponding to said inlet zone sector and with pump-generated discharge pressure over an area corresponding to said outlet zone sector.

2. In combination, casing means for journaling the driving and driven gears of a gear pump, a pair of wafer members and a webbed resilient gasket interposed between said pair of wafer members, said gasket including an outer peripherally continuous Web, a pair of inner peripherally continuous webs circumjacent each of said bushings, and cross webs together with said inner and outer webs forming an inlet zone sector in said gasket on the inlet side of the pump and an outlet zone sector in said gasket on the outlet side of the pump, a rigid pressure plate for each gear, each having a motive surface engaged by an adjoining portion of one of said wafer members and each having a sealing surface for engaging the adjoining gear side face, said one wafer member having openings formed therein communicating said inlet zone sector with the inlet side of the pump and communicating said outlet zone sector with the outlet side of the pump for pressure loading said pressure plates, said casing means including abutment shoulders for clamping the outer peripheral edge of said water members, and means including said casing means on the axial outer side of the other of said wafer members forming a shoulder adjacent the outer of said water members for holding the wafer members and gasket inwardly against the pressure plates to maintain the gasket sealingly axially squeezed between the wafer members with said gasket being axially expandible to maintain sealing relationship with the wafer members.

3. In combination, casing means for journaling the driving and driven gears of a gear pump, a pair of wafer members, a webbed resilient gasket interposed between said pair of wafer members and including an outer peripherally continuous web, a pair of inner peripherally continuous webs circumjacent each of said bushings, and cross webs together with said inner and outer webs forming an inlet zone sector in said gasket on the inlet side of the pump and an outlet Zone sector in said gasket on the outlet side of the pump, and a rigid pressure plate for each gear and each having a motive surface engaged by an adjoining portion of one of said water members and each having a sealing surface for engaging the adjoining gear side face, said one wafer member having openings formed therein communicating said inlet zone sector with the inlet side of the pump and communicating said outlet zone sector with the outlet side of the pump for pressure loading said pressure plates, at third wafer member corresponding in size and shape to the inlet zone sector and being interposed between said first and second wafers at said inlet zone to support the adjoining webbing of said gasket against pressure displacement, said casing means having portions clamping said Wafer members together, and a means including said casing means axially outwardly of the outer of said pair of wafer members for holding the wafer members and gasket inwardly against the pressure plates to maintain the gasket sealingly axially squeezed between the wafer members with said gasket being axially expandible to maintain sealing relationship with said wafer members.

4. In combination, a pair of water members and a webbed rubber gasket interposed therebetween, said wafer members being made of a sheet form material of sutficient thinness to be somewhat flexible, said gasket including an outer peripherally continuous web, a pair of inner peripherally continuous webs forming shaft openings and cross webs together with said inner and outer webs forming an inlet zone sector and an outlet zone sector adapted to be positioned opposite the inlet and outlet zones of a pump, a rigid pressure plate means having a corresponding pair of shaft openings and including a motive surface engaged by an adjoining portion of one of said water members inwardly of the outer web and having an opposite sealing surface adapted to engage the adjoining side face of a pump rotary fluid displacement means, said one water member having openings formed therein for communicating the inlet zone sector with the inlet side of the pump and communicating the outlet zone sector with the outlet side of the pump, thereby to pressure-load the pressure plate means when assembled in a pump, and pump casing means clamping said pair of water members at the peripheral area axially opposite the outer web of said gasket, and for holding the wafer members and gasket axially inwardly toward the pressure plates to maintain the gasket sealingly axially squeezed between the Wafer members with said gasket being axially expandible to maintain sealing relationship with said wafer members.

References Cited in the file of this patent UNITED STATES PATENTS 2,044,873 Beust June 23, 1936 2,702,509 Garnier Feb. 22, 1955 2,756,681 Oliver July 31, 1956 2,772,638 Nagely Dec. 4, 1956 2,809,592 Miller et a1 Oct. 15, 1957 2,816,510 Jarvis Dec. '17, 1957 FOREIGN PATENTS 523,969 Italy Apr. 19, 1955 815,501 Great Britain June 24, 1959 1,121,180 France Apr. 30, 1956 

